[clang] Be careful when choosing "fast path" for initialization with #embed

clang/lib/Sema/SemaInit.cpp

@@ -1993,9 +1993,18 @@ static bool checkDestructorReference(QualType ElementType, SourceLocation Loc,
   return SemaRef.DiagnoseUseOfDecl(Destructor, Loc);
 }
 
-static bool canInitializeArrayWithEmbedDataString(ArrayRef<Expr *> ExprList,
-                                                  QualType InitType,
-                                                  ASTContext &Context) {
+static bool
+canInitializeArrayWithEmbedDataString(ArrayRef<Expr *> ExprList,
+                                      const InitializedEntity &Entity,
+                                      ASTContext &Context) {
+  QualType InitType = Entity.getType();
+  const InitializedEntity *Parent = &Entity;
+
+  while (Parent) {
+    InitType = Parent->getType();
+    Parent = Parent->getParent();
+  }
+
   // Only one initializer, it's an embed and the types match;
   EmbedExpr *EE =
       ExprList.size() == 1
@@ -2034,7 +2043,7 @@ void InitListChecker::CheckArrayType(const InitializedEntity &Entity,
     }
   }
 
-  if (canInitializeArrayWithEmbedDataString(IList->inits(), DeclType,
+  if (canInitializeArrayWithEmbedDataString(IList->inits(), Entity,
                                             SemaRef.Context)) {
     EmbedExpr *Embed = cast<EmbedExpr>(IList->inits()[0]);
     IList->setInit(0, Embed->getDataStringLiteral());

clang/test/Preprocessor/embed_codegen.cpp

@@ -3,6 +3,7 @@
 // CHECK: @__const._Z3fooi.ca = private unnamed_addr constant [3 x i32] [i32 0, i32 106, i32 107], align 4
 // CHECK: @__const._Z3fooi.sc = private unnamed_addr constant %struct.S1 { i32 106, i32 107, i32 0 }, align 4
 // CHECK: @__const._Z3fooi.t = private unnamed_addr constant [3 x %struct.T] [%struct.T { [2 x i32] [i32 48, i32 49], %struct.S1 { i32 50, i32 51, i32 52 } }, %struct.T { [2 x i32] [i32 53, i32 54], %struct.S1 { i32 55, i32 56, i32 57 } }, %struct.T { [2 x i32] [i32 10, i32 0], %struct.S1 zeroinitializer }], align 16
+// CHECK: @__const._Z3fooi.W = private unnamed_addr constant %struct.Wrapper { i32 48, %struct.HasCharArray { [10 x i8] c"123456789\0A" } }, align 4
 void foo(int a) {
 // CHECK: %a.addr = alloca i32, align 4
 // CHECK: store i32 %a, ptr %a.addr, align 4
@@ -81,4 +82,11 @@ struct T tnonc[] = {
 #embed <jk.txt> prefix(,)
 };
 
+
+struct HasCharArray { unsigned char h[10]; };
+struct Wrapper { int a; struct HasCharArray d;  };
+constexpr struct Wrapper W = {
+#embed "numbers.txt"
+};
+
 }

clang/test/Preprocessor/embed_constexpr.cpp

@@ -95,3 +95,11 @@ struct ST {};
 ST<
 #embed <jk.txt> limit(1)
 > st;
+
+struct HasCharArray { unsigned char h[10]; };
+struct Wrapper { int a; struct HasCharArray d;  };
+constexpr struct Wrapper W = {
+#embed "numbers.txt"
+};
+
+static_assert(W.d.h[2] == '3');